scripts: west_commands: completion: Fix linter issues

Fix issues reported by ruff.

Signed-off-by: Pieter De Gendt <pieter.degendt@basalte.be>

.ruff-excludes.toml

@@ -1086,10 +1086,6 @@
     "I001",     # https://docs.astral.sh/ruff/rules/unsorted-imports
     "UP032",    # https://docs.astral.sh/ruff/rules/f-string
 ]
-"./scripts/west_commands/completion.py" = [
-    "UP015",    # https://docs.astral.sh/ruff/rules/redundant-open-modes
-    "UP032",    # https://docs.astral.sh/ruff/rules/f-string
-]
 "./scripts/west_commands/debug.py" = [
     "I001",     # https://docs.astral.sh/ruff/rules/unsorted-imports
     "UP008",    # https://docs.astral.sh/ruff/rules/super-call-with-parameters

scripts/west_commands/completion.py

@@ -88,7 +88,7 @@ class Completion(WestCommand):
         cf += '.' + self._EXT_MAPPING[args.shell[0]]
 
         try:
-            with open(cf, 'r') as f:
+            with open(cf) as f:
                 print(f.read())
         except FileNotFoundError as e:
-            self.die('Unable to find completion file: {}'.format(e))
+            self.die(f'Unable to find completion file: {e}')